1. Field of the Invention
Advanced high performance aircraft require an oxygen delivery system to supply breathing gas to aircraft crew members that is neither too high in oxygen content as to result in hyperoxia or too low so as to prevent hypoxia resulting in crew member fatigue or hyperventilation. Currently designed pneumatic regulators are not sufficiently accurate or responsive to changed conditions causing excessive oxygen in the breathing mixture under some conditions and insufficient oxygen under others.
The present invention is an improved dilution control oxygen regulator that provides a prescribed pressure and oxygen concentration based on altitude.
2. Description of the Prior Art
Several prior patents have been issued for devices pertaining to the regulation of an oxygen air mixture. U.S. Pat. No. 4,121,578 by Torzala discloses an aircraft oxygen regulator which supplies the recipient with a mixture of breathable fluid proportional to the altitude at which the aircraft is flying. The feed mixture is modified by determining the amount of inspired oxygen utilized during each breath and comparing the same with a reference for the recipient. A feedback signal indicative of a recipient's physiological needs is used to operate an oxygen regulator. U.S. Pat. No. 4,340,044 by Levy et al discloses a medical ventilator for switching and mixing oxygen with air with a servocontrol device and logic circuitry. U.S. Pat. No. 4,335,735 by Cramer et al discloses an oxygen regulator for controlling the flow of breathing oxygen that includes a balanced oxygen valve and air valve which cooperate with a dilution aneroid valve. U.S. Pat. No. 2,897,833 by Seeler discloses a pressure control dilution valve for maintaining a constant pressure at its outlet regardless of the mixture ratio of air and oxygen used. U.S. Pat. No. 3,875,957 by Viet et al teaches an oxygen-air dilution in three different modes of operation to provide normal air dilution, 100% oxygen and pressure breathing. U.S. Pat. No. 4,274,404 by Molzan et al discloses an oxygen supply system for human inhalation of oxygen with an oxygen pressure regulator and a means to shut-off oxygen from the source when a build-up of oxygen pressure exists. However, none of the references teach a combination of the features of the present invention which includes a controller for biasing oxygen and air valves based on a prescribed pressure command and oxygen concentration schedule.